The following box plot shows the U.S. population for 1990, the latest available year. (Source: Bureau of the Census, 1990 Census)
Are there fewer or more children (age 17 and under) than senior citizens (age 65 and over)? How do you know?
12.6% are age 65 and over. Approximately what percent of the population are of working age adults (above age 17 to age 65)?
more children
62.4%
Javier and Ercilia are supervisors at a shopping mall. Each was given the task of estimating the mean distance that shoppers live from the mall. They each randomly surveyed 100 shoppers. The samples yielded the following information:
Javier
Ercilla
6.0 miles
6.0 miles
4.0 miles
7.0 miles
How can you determine which survey was
correct?
Explain what the difference in the results of the surveys implies about the data.
If the two histograms depict the distribution of values for each supervisor, which one depicts Ercilia's sample? How do you know?
If the two box plots depict the distribution of values for each supervisor, which one depicts Ercilia’s sample? How do you know?
Student grades on a chemistry exam were:
77, 78, 76, 81, 86, 51, 79, 82, 84, 99
Construct a stem-and-leaf plot of the data.
Are there any potential outliers? If so, which scores are they? Why do you consider them outliers?
51,99
Try these multiple choice questions.
The next three questions refer to the following information. We are interested in the number of years students in a particular elementary statistics class have lived in California.
The information in the following table is from the entire section.
Number of years
Frequency
Total = 20
7
1
14
3
15
1
18
1
19
4
20
3
22
1
23
1
26
1
40
2
42
2
What is the IQR?
8
11
15
35
A
What is the mode?
19
19.5
14 and 20
22.65
A
Is this a sample or the entire population?
sample
entire population
neither
B
The next two questions refer to the following table.
= the number of days per week that 100 clients use a particular exercise facility.
X
Frequency
0
3
1
12
2
33
3
28
4
11
5
9
6
4
The 80th percentile is:
5
80
3
4
D
The number that is 1.5 standard deviations BELOW the mean is approximately:
0.7
4.8
-2.8
Cannot be determined
A
The next two questions refer to the following histogram. Frederico recently opened a "designer" T-shirt store near the beach. During the first month of operation, he conducted a marketing survey of a random sample of 111 customers. One of the questions asked the customer how many T-shirts he/she owns that cost more than $19 each.
The percent of people that own at most three (3) T-shirts costing more than $19 each is approximately:
21
59
41
Cannot be determined
C
If the data were collected by asking the first 111 people who entered the store, then the type of sampling is:
cluster
simple random
stratified
convenience
D
A music school has budgeted to purchase 3 musical instruments. They plan to purchase a piano costing $3000, a guitar costing $550, and a drum set costing $600. The average cost for a piano is $4,000 with a standard deviation of $2,500.
The average cost for a guitar is $500 with a standard deviation of $200. The average cost for drums is $700 with a standard deviation of $100. Which cost is the lowest, when compared to other instruments of the same type? Which cost is the highest when compared to other instruments of the same type. Justify your answer numerically.
For pianos, the cost of the piano is 0.4 standard deviations BELOW average. For guitars, the cost of the guitar is 0.25 standard deviations ABOVE average. For drums, the cost of the drum set is 1.0 standard deviations BELOW average. Of the three, the drums cost the lowest in comparison to the cost of other instruments of the same type. The guitar cost the most in comparison to the cost of other instruments of the same type.
Suppose that a publisher conducted a survey asking adult consumers the number of fiction paperback books they had purchased in the previous month. The results are summarized in the table below. (Note that this is the data presented for publisher B in homework exercise 13).
Publisher b
# of
books
Freq.
Rel.
Freq.
0
18
1
24
2
24
3
22
4
15
5
10
7
5
9
1
Are there any outliers in the data? Use an appropriate numerical test involving the IQR to identify outliers, if any, and clearly state your conclusion.
If a data value is identified as an outlier, what should be done about it?
Are any data values further than 2 standard deviations away from the mean? In some situations, statisticians may use this criteria to identify data values that are unusual, compared to the other data values. (Note that this criteria is most appropriate to use for data that is mound-shaped and symmetric, rather than for skewed data.)
Do parts (a) and (c) of this problem this give the same answer?
Examine the shape of the data. Which part, (a) or (c), of this question gives a more appropriate result for this data?
Based on the shape of the data which is the most appropriate measure of center for this data: mean, median or mode?
IQR = 4 – 1 = 3 ; Q1 – 1.5*IQR = 1 – 1.5(3) = -3.5 ; Q3 + 1.5*IQR = 4 + 1.5(3) = 8.5 ;The data value of 9 is larger than 8.5. The purchase of 9 books in one month is an outlier.
The outlier should be investigated to see if there is an error or some other problem in the data; then a decision whether to include or exclude it should be made based on the particular situation.
If it was a correct value then the data value should remain in the data set. If there is a problem with this data value, then it should be corrected or removed from the data. For example: If the data was recorded incorrectly (perhaps a 9 was miscoded and the correct value was 6) then the data should be corrected. If it was an error but the correct value is not known it should be removed from the data set.
xbar – 2s = 2.45 – 2*1.88 = -1.31 ; xbar + 2s = 2.45 + 2*1.88 = 6.21 ; Using this method, the five data values of 7 books purchased and the one data value of 9 books purchased would be considered unusual.
No: part (a) identifies only the value of 9 to be an outlier but part (c) identifies both 7 and 9.
The data is skewed (to the right). It would be more appropriate to use the method involving the IQR in part (a), identifying only the one value of 9 books purchased as an outlier. Note that part (c) remarks that identifying unusual data values by using the criteria of being further than 2 standard deviations away from the mean is most appropriate when the data are mound-shaped and symmetric.
The data are skewed to the right. For skewed data it is more appropriate to use the median as a measure of center.
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
Receive real-time job alerts and never miss the right job again
Source:
OpenStax, Collaborative statistics homework book: custom version modified by r. bloom. OpenStax CNX. Dec 23, 2009 Download for free at http://legacy.cnx.org/content/col10619/1.2
Google Play and the Google Play logo are trademarks of Google Inc.
Notification Switch
Would you like to follow the 'Collaborative statistics homework book: custom version modified by r. bloom' conversation and receive update notifications?
